Systems and methods for resolution consistent semantic zooming

ABSTRACT

Systems and methods according to the present invention provide a control framework for organizing, selecting and launching media items including graphical user interfaces coupled with an optional free space control device for collection of the basic control primitives of point, click, scroll, hover and zoom which permit for easy and rapid selection of media items, e.g., movies, songs etc., from large or small collections. The remote control maps natural hand movements and gestures into relevant commands while the graphical display uses images, zooming for increased/decreased levels of detail and continuity of GUI objects to provide easy organization, selection and navigation among the media items by a user.

RELATED APPLICATIONS

This application is related to, and claims priority from, U.S.Provisional Patent Application Ser. No. 60/468,830 filed on May 8, 2003,entitled “A Zoomable Interface that Organizes, Manages and Plays MediaItems”. This application is also related to, and claims priority from,U.S. Provisional Patent Application Ser. No. 60/495,998, filed on Aug.18, 2003, entitled “A Control Framework with a Zoomable Graphical UserInterface for Organizing, Selecting and Launching Media Items”, thedisclosure of which is incorporated here by reference.

BACKGROUND

The present invention describes a framework for organizing, selectingand launching media items. Part of that framework involves the designand operation of graphical user interfaces with the basic buildingblocks of point, click, scroll, hover and zoom and, more particularly,to graphical user interfaces associated with media items which can beused with a free-space pointing remote.

Technologies associated with the communication of information haveevolved rapidly over the last several decades. Television, cellulartelephony, the Internet and optical communication techniques (to namejust a few things) combine to inundate consumers with three decades haveseen the introduction of cable television service, satellite televisionservice, pay-per-view movies and video-on-demand. Whereas televisionviewers of the 1960s could typically receive perhaps four or fiveover-the-air TV channels on their television sets, today's TV watchershave the opportunity to select from hundreds and potentially thousandsof channels of shows and information. Video-on-demand technology,currently used primarily in hotels and the like, provides the potentialfor in-home entertainment selection from among thousands of movietitles. Digital video recording (DVR) equipment such as offered by TiVo,Inc., 2160 Gold Street, Alviso, Calif. 95002, further expand theavailable choices.

The technological ability to provide so much information and content toend users provides both opportunities and challenges to system designersand service providers. One challenge is that while end users typicallyprefer having more choices rather than fewer, this preference iscounterweighted by their desire that the selection process be both fastand simple. Unfortunately, the development of the systems and interfacesby which end users access media items has resulted in selectionprocesses which are neither fast nor simple. Consider again the exampleof television programs. When television was in its infancy, determiningwhich program to watch was a relatively simple process primarily due tothe small number of choices. One would consult a printed guide which wasformatted, for example, as series of columns and rows which showed thecorrespondence between (1) nearby television channels, (2) programsbeing transmitted on those channels and (3) date and time. Thetelevision was tuned to the desired channel by adjusting a tuner knoband the viewer watched the selected program. Later, remote controldevices were introduced that permitted viewers to tune the televisionfrom a distance. This addition to the user-television interface createdthe phenomenon known as “channel surfing” whereby a viewer could rapidlyview short segments being broadcast on a number of channels to quicklylearn what programs were available at any given time.

Despite the fact that the number of channels and amount of viewablecontent has dramatically increased, the generally available userinterface and control device options and framework for televisions hasnot changed much over the last 30 years. Printed guides are still themost prevalent mechanism for conveying programming information. Themultiple button remote control with simple up and down arrows is stillthe most prevalent channel/content selection mechanism. The reaction ofthose who design and implement the TV user interface to the increase inavailable media content has been a straightforward extension of theexisting selection procedures and interface objects. Thus, the number ofrows and columns in the printed guides has been increased to accommodatemore channels. The number of buttons on the remote control devices hasbeen increased to support additional functionality and content handling,e.g., as shown in FIG. 1. However, this approach has significantlyincreased both the time required for a viewer to review the availableinformation and the complexity of actions required to implement aselection. Arguably, the cumbersome nature of the existing interface hashampered commercial implementation of some services, e.g.,video-on-demand, since consumers are resistant to new services that willadd complexity to an interface that they view as already too slow andcomplex.

In addition to increases in bandwidth and content, the user interfacebottleneck problem, is being exacerbated by the aggregation oftechnologies. Consumers are reacting positively to having the option ofbuying integrated systems rather than a number of segregable components.A good example of this trend is the combination television/VCR/DVD inwhich three previously independent components are frequently sold todayas an integrated unit. This trend is likely to continue, potentiallywith an end result that most if not all of the communication devicescurrently found in the household being packaged as an integrated unit,e.g., a television/VCR/DVD/internet access/radio/stereo unit. Even thosewho buy separate components desire seamless control of, and interworkingbetween, those components. With this increased aggregation comes thepotential for more complexity in the user interface. For example, whenso-called “universal” remote units were introduced, e.g., to combine thefunctionality of TV remote units and VCR remote units, the number ofbuttons on these universal remote units was typically more than thenumber of buttons on either the TV remote unit or VCR remote unitindividually. This added number of buttons and functionality makes itvery difficult to control anything but the simplest aspects of a TV orVCR without hunting for exactly the right button on the remote. Manytimes, these universal remotes do not provide enough buttons to accessmany levels of control or features unique to certain TVs. In thesecases, the original device remote unit is still needed, and the originalhassle of handling multiple remotes remains due to user interface issuesarising from the complexity of aggregation. Some remote units haveaddressed this problem by adding “soft” buttons that can be programmedwith the expert commands. These soft buttons sometimes have accompanyingLCD displays to indicate their action. These too have the flaw that theyare difficult to use without looking away from the TV to the remotecontrol. Yet another flaw in these remote units is the use of modes inan attempt to reduce the number of buttons. In these “moded” universalremote units, a special button exists to select whether the remoteshould communicate with the TV, DVD player, cable set-top box, VCR, etc.This causes many usability issues including sending commands to thewrong device, forcing the user to look at the remote to make sure thatit is in the right mode, and it does not provide any simplification tothe integration of multiple devices. The most advanced of theseuniversal remote units provide some integration by allowing the user toprogram sequences of commands to multiple devices into the remote. Thisis such a difficult task that many users hire professional installers toprogram their universal remote units.

Some attempts have also been made to modernize the screen interfacebetween end users and media systems. Electronic program guides (EPGs)have been developed and implemented to replace the afore-described mediaguides. Early EPGs provided what was essentially an electronic replicaof the printed media guides. For example, cable service operators haveprovided analog EPGs wherein a dedicated channel displays a slowlyscrolling grid of the channels and their associated programs over acertain time horizon, e.g., the next two hours. Scrolling through evenone hundred channels in this way can be tedious and is not feasiblyscalable to include significant additional content deployment, e.g.,video-on-demand. More sophisticated digital EPGs have also beendeveloped. In digital EPGs, program schedule information, and optionallyapplications/system software, is transmitted to dedicated EPG equipment,e.g., a digital set-top box (STB). Digital EPGs provide more flexibilityin designing the user interface for media systems due to their abilityto provide local interactivity and to interpose one or more interfacelayers between the user and the selection of the media items to beviewed. An example of such an interface can be found in U.S. Pat. No.6,421,067 to Kamen et al., the disclosure of which is incorporated hereby reference. FIG. 2 depicts a GUI described in the '067 patent.Therein, according to the Kamen et al. patent, a first column 190 listsprogram channels, a second column 191 depicts programs currentlyplaying, a column 192 depicts programs playing in the next half-hour,and a fourth column 193 depicts programs playing in the half hour afterthat. The baseball bat icon 121 spans columns 191 and 192, therebyindicating that the baseball game is expected to continue into the timeslot corresponding to column 192. However, text block 111 does notextend through into column 192. This indicates that the football game isnot expected to extend into the time slot corresponding to column 192.As can be seen, a pictogram 194 indicates that after the football game,ABC will be showing a horse race. The icons shown in FIG. 2 can beactuated using a cursor, not shown, to implement various features, e.g.,to download information associated with the selected programming. Otherdigital EPGs and related interfaces are described, for example, in U.S.Pat. Nos. 6,314,575, 6,412,110, and 6,577,350, the disclosures of whichare also incorporated here by reference.

However, the interfaces described above suffer from, among otherdrawbacks, an inability to easily scale between large collections ofmedia items and small collections of media items. For example,interfaces which rely on lists of items may work well for smallcollections of media items, but are tedious to browse for largecollections of media items. Interfaces which rely on hierarchicalnavigation (e.g., tree structures) may be more speedy to traverse thanlist interfaces for large collections of media items, but are notreadily adaptable to small collections of media items. Additionally,users tend to lose interest in selection processes wherein the user hasto move through three or more layers in a tree structure. For all ofthese cases, current remote units make this selection processor evenmore tedious by forcing the user to repeatedly depress the up and downbuttons to navigate the list or hierarchies. When selection skippingcontrols are available such as page up and page down, the user usuallyhas to look at the remote to find these special buttons or be trained toknow that they even exist.

Accordingly, it would be desirable to provide organizing frameworks,techniques and systems which simplify the control and screen interfacebetween users and media systems as well as accelerate the selectionprocess, while at the same time permitting service providers to takeadvantage of the increases in available bandwidth to end user equipmentby facilitating the supply of a large number of media items and newservices to the user. Moreover, it would be desirable to provideinterfaces which supply an easy and fast selection experience regardlessof the size(s) of the media item collection(s) being browsed.

SUMMARY

Systems and methods according to the present invention address theseneeds and others by providing a total control framework for organizing,selecting and launching media items including a user interface frameworkwhich then provides for easy and rapid selection of media items. Controlof the framework can employ a free space pointing device that includes aminimal set of buttons and scroll wheel for pointing, clicking andscrolling through selections on an associated graphical user interface.This exemplary graphical user interface (GUI) provides feedback to theuser through the use of an on-screen pointer, graphical animations whenthe pointer hovers over selections, and zooming into and out ofselections to smoothly navigate between overview and detail screens.Exemplary embodiments of the present invention employ images, zoomingfor increased/decreased levels of detail and continuity of GUI objectswhich permit easy navigation by a user. Graphical user interfacesaccording to the present invention organize media item selections on avirtual surface. Similar selections can be grouped together. Initially,the interface presents a zoomed out view of the surface, and in mostcases, the actual selections will not be visible in full detail at thislevel. As the user zooms progressively inward, more details are revealedconcerning the media item groups or selections. At different zoomlevels, different controls are available so that the user can playgroups of selections, individual selections, or go to another part ofthe virtual surface to browse other related media items.

According to one exemplary embodiment of the present invention, a methodfor displaying an interface object on a graphical user interface (GUI)comprises the steps of: displaying said interface object at one of aplurality of magnification levels, hiding at least one detail of theinterface object at the one of the plurality of magnification levels,displaying the interface object at another of the plurality ofmagnification levels, and revealing the at least one detail of theinterface object at the predetermined another of the plurality ofmagnification levels, regardless of a resolution at which the interfaceobject is displayed.

According to another exemplary embodiment of the present invention, amedia controller comprises: a processor for displaying a plurality ofmedia items as images on a display screen, an input port for receivinginput, means for zooming in on the plurality of media items based on afirst input until at least one control object is visible on the displayscreen and means for playing a media item associated with the at leastone control object in response to a second input.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate exemplary embodiments of thepresent invention, wherein:

FIG. 1 depicts a conventional remote control unit for an entertainmentsystem;

FIG. 2 depicts a conventional graphical user interface for anentertainment system;

FIG. 3 depicts an exemplary media system in which exemplary embodimentsof the present invention (both display and remote control) can beimplemented;

FIG. 4 shows a system controller of FIG. 3 in more detail;

FIGS. 5-8 depict a graphical user interface for a media system accordingto an exemplary embodiment of the present invention;

FIG. 9 illustrates an exemplary data structure according to an exemplaryembodiment of the present invention;

FIGS. 10( a) and 10(b) illustrate a zoomed out and a zoomed in versionof a portion of an exemplary GUI created using the data structure ofFIG. 9 according to an exemplary embodiment of the present invention;

FIG. 11 depicts a doubly linked, ordered list used to generated GUIdisplays according to an exemplary embodiment of the present invention;

FIGS. 12( a) and 12(b) show a zoomed out and a zoomed in version of aportion of another exemplary GUI used to illustrate operation of a nodewatching algorithm according to an exemplary embodiment of the presentinvention;

FIGS. 13( a) and 13(b) depict exemplary data structures used toillustrate operation of the node watching algorithm as it the GUItransitions from the view of FIG. 12( a) to the view of FIG. 12( b)according to an exemplary embodiment of the present invention;

FIG. 14 depicts a data structure according to another exemplaryembodiment of the present invention including a virtual camera for usein resolution consistent zooming;

FIGS. 15( a) and 15(b) show a zoomed out and zoomed in version of aportion of an exemplary GUI which depict semantic zooming according toan exemplary embodiment of the present invention;

FIGS. 16-20 depict a zoomable graphical user interface according toanother exemplary embodiment of the present invention;

FIG. 21 illustrates an exemplary set of overlay controls which can beprovided according to exemplary embodiments of and the present inventionand;

FIG. 22 illustrates an exemplary framework for implementing zoomablegraphical user interfaces according to the present invention.

DETAILED DESCRIPTION

The following detailed description of the invention refers to theaccompanying drawings. The same reference numbers in different drawingsidentify the same or similar elements. Also, the following detaileddescription does not limit the invention. Instead, the scope of theinvention is defined by the appended claims.

In order to provide some context for this discussion, an exemplaryaggregated media system 200 in which the present invention can beimplemented will first be described with respect to FIG. 3. Thoseskilled in the art will appreciate, however, that the present inventionis not restricted to implementation in this type of media system andthat more or fewer components can be included therein. Therein, aninput/output (I/O) bus 210 connects the system components in the mediasystem 200 together. The I/O bus 210 represents any of a number ofdifferent of mechanisms and techniques for routing signals between themedia system components. For example, the I/O bus 210 may include anappropriate number of independent audio “patch” cables that route audiosignals, coaxial cables that route video signals, two-wire serial linesor infrared or radio frequency transceivers that route control signals,optical fiber or any other routing mechanisms that route other types ofsignals.

In this exemplary embodiment, the media system 200 includes atelevision/monitor 212, a video cassette recorder (VCR) 214, digitalvideo disk (DVD) recorder/playback device 216, audio/video tuner 218 andcompact disk player 220 coupled to the I/O bus 210. The VCR 214, DVD 216and compact disk player 220 may be single disk or single cassettedevices, or alternatively may be multiple disk or multiple cassettedevices. They may be independent units or integrated together. Inaddition, the media system 200 includes a microphone/speaker system 222,video camera 224 and a wireless I/O control device 226. According toexemplary embodiments of the present invention, the wireless I/O controldevice 226 is a media system remote control unit that supports freespace pointing, has a minimal number of buttons to support navigation,and communicates with the entertainment system 200 through RF signals.For example, wireless I/O control device 226 can be a free-spacepointing device which uses a gyroscope or other mechanism to define botha screen position and a motion vector to determine the particularcommand desired. A set of buttons can also be included on the wirelessI/O device 226 to initiate the “click” primitive described below as wellas a “back” button. In another exemplary embodiment, wireless I/Ocontrol device 226 is a media system remote control unit, whichcommunicates with the components of the entertainment system 200 throughIR signals. In yet another embodiment, wireless I/O control device 134may be an IR remote control device similar in appearance to a typicalentertainment system remote control with the added feature of atrack-ball or other navigational mechanisms which allows a user toposition a cursor on a display of the entertainment system 100.

The entertainment system 200 also includes a system controller 228.According to one exemplary embodiment of the present invention, thesystem controller 228 operates to store and display entertainment systemdata available from a plurality of entertainment system data sources andto control a wide variety of features associated with each of the systemcomponents. As shown in FIG. 3, system controller 228 is coupled, eitherdirectly or indirectly, to each of the system components, as necessary,through I/O bus 210. In one exemplary embodiment, in addition to or inplace of I/O bus 210, system controller 228 is configured with awireless communication transmitter (or transceiver), which is capable ofcommunicating with the system components via IR signals or RF signals.Regardless of the control medium, the system controller 228 isconfigured to control the media components of the media system 200 via agraphical user interface described below.

As further illustrated in FIG. 3, media system 200 may be configured toreceive media items from various media sources and service providers. Inthis exemplary embodiment, media system 200 receives media input fromand, optionally, sends information to, any or all of the followingsources: cable broadcast 230, satellite broadcast 232 (e.g., via asatellite dish), very high frequency (VHF) or ultra high frequency (UHF)radio frequency communication of the broadcast television networks 234(e.g., via an aerial antenna), telephone network 236 and cable modem 238(or another source of Internet content). Those skilled in the art willappreciate that the media components and media sources illustrated anddescribed with respect to FIG. 3 are purely exemplary and that mediasystem 200 may include more or fewer of both. For example, other typesof inputs to the system include AM/FM radio and satellite radio.

FIG. 4 is a block diagram illustrating an embodiment of an exemplarysystem controller 228 according to the present invention. Systemcontroller 228 can, for example, be implemented as a set-top box andincludes, for example, a processor 300, memory 302, a display controller304, other device controllers (e.g., associated with the othercomponents of system 200), one or more data storage devices 308 and anI/O interface 310. These components communicate with the processor 300via bus 312. Those skilled in the art will appreciate that processor 300can be implemented using one or more processing units. Memory device(s)302 may include, for example, DRAM or SRAM, ROM, some of which may bedesignated as cache memory, which store software to be run by processor300 and/or data usable by such programs, including software and/or dataassociated with the graphical user interfaces described below. Displaycontroller 304 is operable by processor 300 to control the display ofmonitor 212 to, among other things, display GUI screens and objects asdescribed below. Zoomable GUIs according to exemplary embodiments of thepresent invention provide resolution independent zooming, so thatmonitor 212 can provide displays at any resolution. Device controllers306 provide an interface between the other components of the mediasystem 200 and the processor 300. Data storage 308 may include one ormore of a hard disk drive, a floppy disk drive, a CD-ROM device, orother mass storage device. Input/output interface 310 may include one ormore of a plurality of interfaces including, for example, a keyboardinterface, an RF interface, an IR interface and a microphone/speechinterface. According to one exemplary embodiment of the presentinvention, I/O interface 310 will include an interface for receivinglocation information associated with movement of a wireless pointingdevice.

Generation and control of a graphical user interface according toexemplary embodiments of the present invention to display media itemselection information is performed by the system controller 228 inresponse to the processor 300 executing sequences of instructionscontained in the memory 302. Such instructions may be read into thememory 302 from other computer-readable mediums such as data storagedevice(s) 308 or from a computer connected externally to the mediasystem 200. Execution of the sequences of instructions contained in thememory 302 causes the processor to generate graphical user interfaceobjects and controls, among other things, on monitor 212. In alternativeembodiments, hard-wire circuitry may be used in place of or incombination with software instructions to implement the presentinvention. As mentioned in the Background section, conventionalinterface frameworks associated with the television industry areseverely limited in their ability to provide users with a simple and yetcomprehensive selection experience. Accordingly, control frameworksdescribed herein overcome these limitations and are, therefore, intendedfor use with televisions, albeit not exclusively. It is also anticipatedthat the revolutionary control frameworks, graphical user interfacesand/or various algorithms described herein will find applicability tointerfaces which may be used with computers and other non-televisiondevices. In order to distinguish these various applications of exemplaryembodiments of the present invention, the terms “television” and “TV”are used in this specification to refer to a subset of display devices,whereas the terms “GUI”, “GUI screen”, “display” and “display screen”are intended to be generic and refer to television displays, computerdisplays and any other display device. More specifically, the terms“television” and “TV” are intended to refer to the subset of displaydevices which are able to display television signals (e.g., NTSCsignals, PAL signals or SECAM signals) without using an adapter totranslate television signals into another format (e.g., computer videoformats). In addition, the terms “television” and “TV” refer to a subsetof display devices that are generally viewed from a distance of severalfeet or more (e.g., sofa to a family room TV) whereas computer displaysare generally viewed close-up (e.g., chair to a desktop monitor).

Having described an exemplary media system which can be used toimplement control frameworks including zoomable graphical interfacesaccording to the present invention, several examples of such interfaceswill now be described. According to exemplary embodiments of the presentinvention, a user interface displays selectable items which can begrouped by category. A user points a remote unit at the category orcategories of interest and depresses the selection button to zoom in orthe “back” button to zoom back. Each zoom in, or zoom back, action by auser results in a change in the magnification level and/or context ofthe selectable items rendered by the user interface on the screen.According to exemplary embodiments, each change in magnification levelcan be consistent, i.e., the changes in magnification level are providedin predetermined steps. Exemplary embodiments of the present inventionalso provide for user interfaces which incorporate several visualtechniques to achieve scaling to the very large. These techniquesinvolve a combination of building blocks and techniques that achieveboth scalability and ease-of-use, in particular techniques which adaptthe user interface to enhance a user's visual memory for rapidre-visiting of user interface objects.

The user interface is largely a visual experience. In such anenvironment exemplary embodiments of the present invention make use ofthe capability of the user to remember the location of objects withinthe visual environment. This is achieved by providing a stable,dependable location for user interface selection items. Each object hasa location in the zoomable layout. Once the user has found an object ofinterest it is natural to remember which direction was taken to locatethe object. If that object is of particular interest it is likely thatthe user will re-visit the item more than once, which will reinforce theuser's memory of the path to the object. User interfaces according toexemplary embodiments of the present invention provide visual mnemonicsthat help the user remember the location of items of interest. Suchvisual mnemonics include pan and zoom animations, transition effectswhich generate a geographic sense of movement across the userinterface's virtual surface and consistent zooming functionality, amongother things which will become more apparent based on the examplesdescribed below.

Organizing mechanisms are provided to enable the user to select fromextremely large sets of items while being shielded from the detailsassociated with large selection sets. Various types of organizingmechanisms can be used in accordance with the present invention andexamples are provided below.

Referring first to FIGS. 5-8, an exemplary control framework including azoomable graphical user interface according to an exemplary embodimentof the present invention is described for use in displaying andselecting musical media items. FIG. 5 portrays the zoomable GUI at itsmost zoomed out state. Therein, the interface displays a set of shapes500. Displayed within each shape 500 are text 502 and/or a picture 504that describe the group of media item selections accessible via thatportion of the GUI. As shown in FIG. 5, the shapes 500 are rectangles,and text 502 and/or picture 504 describe the genre of the media.However, those skilled in the art will appreciate that this first viewedGUI grouping could represent other aspects of the media selectionsavailable to the user e.g., artist, year produced, area of residence forthe artist, length of the item, or any other characteristic of theselection. Also, the shapes used to outline the various groupings in theGUI need not be rectangles. Shrunk down versions of album covers andother icons could be used to provide further navigational hints to theuser in lieu of or in addition to text 502 and/or picture 504 within theshape groupings 500. A background portion of the GUI 506 can bedisplayed as a solid color or be a part of a picture such as a map toaid the user in remembering the spatial location of genres so as to makefuture uses of the interface require less reading. The selection pointer(cursor) 508 follows the movements of an input device and indicates thelocation to zoom in on when the user presses the button on the device(not shown in FIG. 5).

According to one exemplary embodiment of the present invention, theinput device can be a wireless mouse, e.g., the wireless mousemanufactured by Gyration, Inc.12930 Saratoga Avenue, Bldg.C, Saratoga,Calif. 95070, coupled with a graphical user interface that supports thepoint, click, scroll, hover and zoom building blocks which are describedin more detail below. One feature of this exemplary input device that isbeneficial for use in conjunction with the present invention is that ithas only two buttons and a scroll wheel, i.e., three input actuationobjects. One of the buttons can be configured as a ZOOM IN (select)button and one can be configured as a ZOOM OUT (back) button. Comparedwith the conventional remote control units, e.g., that shown in FIG. 1,the present invention simplifies this aspect of the GUI by greatlyreducing the number of buttons, etc., that a user is confronted with inmaking his or her media item selection. An additional preferred, but notrequired, feature of input devices according to exemplary embodiments ofthe present invention is that they provide “free space pointing”capability for the user. The phrase “free space pointing” is used inthis specification to refer to the ability of a user to freely move theinput device in three (or more) dimensions in the air in front of thedisplay screen and the corresponding ability of the user interface totranslate those motions directly into movement of a cursor on thescreen. Thus “free space pointing” differs from conventional computermouse pointing techniques which use a surface other than the displayscreen, e.g., a desk surface or mousepad, as a proxy surface from whichrelative movement of the mouse is translated into cursor movement on thecomputer display screen. Use of free space pointing in controlframeworks according to exemplary embodiments of the present inventionfurther simplifies the user's selection experience, while at the sametime providing an opportunity to introduce gestures as distinguishableinputs to the interface. A gesture can be considered as a recognizablepattern of movement over time which pattern can be translated into a GUIcommand, e.g., a function of movement in the x, y, z, yaw, pitch androll dimensions or any subcombination thereof. Those skilled in the artwill appreciate, however that any suitable input device can be used inconjunction with zoomable GUIs according to the present invention. Otherexamples of suitable input devices include, but are not limited to,trackballs, touchpads, conventional TV remote control devices, speechinput, any devices which can communicate/translate a user's gesturesinto GUI commands, or any combination thereof. It is intended that eachaspect of the GUI functionality described herein can be actuated inframeworks according to the present invention using at least one of agesture and a speech command. Alternate implementations include usingcursor and/or other remote control keys or even speech input to identifyitems for selection.

FIG. 6 shows a zoomed in view of Genre 3 that would be displayed if theuser selects Genre 3 from FIG. 5, e.g., by moving the cursor 508 overthe area encompassed by the rectangle surrounding Genre 3 on display 212and depressing a button on the input device. The interface can animatethe zoom from FIG. 5 to FIG. 6 so that it is clear to the user that azoom occurred. An example of such an animated zoom/transition effect isdescribed below. Once the shape 516 that contains Genre 3 occupies mostof the screen on display 212, the interface reveals the artists thathave albums in the genre. In this example, seven different artistsand/or their works are displayed. The unselected genres 515 that wereadjacent to Genre 3 in the zoomed out view of FIG. 5 are still adjacentto Genre 3 in the zoomed in view, but are clipped by the edge of thedisplay 212. These unselected genres can be quickly navigated to byselection of them with selection pointer 508. It will be appreciated,however, that other exemplary embodiments of the present invention canomit clipping neighboring objects and, instead, present only theunclipped selections. Each of the artist groups, e.g., group 512, cancontain images of shrunk album covers, a picture of the artist orcustomizable artwork by the user in the case that the category containsplaylists created by the user.

A user may then select one of the artist groups for further reviewand/or selection. FIG. 7 shows a further zoomed in view in response to auser selection of Artist 3 via positioning of cursor 508 and actuationof the input device, in which images of album covers 520 come into view.As with the transition from the GUI screen of FIG. 5 and FIG. 6, theunselected, adjacent artists (artists #2, 6 and 7 in this example) areshown towards the side of the zoomed in display, and the user can clickon these with selection pointer 508 to pan to these artist views. Inthis portion of the interface, in addition to the images 520 of albumcovers, artist information 524 can be displayed as an item in the artistgroup. This information may contain, for example, the artist's picture,biography, trivia, discography, influences, links to web sites and otherpertinent data. Each of the album images 520 can contain a picture ofthe album cover and, optionally, textual data. In the case that thealbum image 520 includes a user created playlist, the graphical userinterface can display a picture which is selected automatically by theinterface or preselected by the user.

Finally, when the user selects an album cover image 520 from within thegroup 521, the interface zooms into the album cover as shown in FIG. 8.As the zoom progresses, the album cover can fade or morph into a viewthat contains items such as the artist and title of the album 530, alist of tracks 532, further information about the album 536, a smallerversion of the album cover 528, and controls 534 to play back thecontent, modify the categorization, link to the artists web page, orfind any other information about the selection. Neighboring albums 538are shown that can be selected using selection pointer 508 to cause theinterface to bring them into view. As mentioned above, alternativeembodiments of the present invention can, for example, zoom in to onlydisplay the selected object, e.g., album 5, and omit the clippedportions of the unselected objects, e.g., albums 4 and 6. This finalzoom provides an example of semantic zooming, wherein certain GUIelements are revealed that were not previously visible at the previouszoom level. Various techniques for performing semantic zooming accordingto exemplary embodiments of the present invention are provided below.

As illustrated in the FIGS. 5-8 and the description, this exemplaryembodiment of a graphical user interface provides for navigation of amusic collection. Interfaces according to the present invention can alsobe used for video collections such as for DVDs, VHS tapes, otherrecorded media, video-on-demand, video segments and home movies. Otheraudio uses include navigation of radio shows, instructional tapes,historical archives, and sound clip collections. Print or text mediasuch as news stories and electronic books can also be organized andaccessed using this invention.

As will be apparent to those skilled in the art from the foregoingdescription, zoomable graphical user interfaces according to the presentinvention provide users with the capability to browse a large (or small)number of media items rapidly and easily. This capability isattributable to many characteristics of interfaces according toexemplary embodiments of the present invention including, but notlimited to: (1) the use of images as all or part of the selectioninformation for a particular media item, (2) the use of zooming torapidly provide as much or as little information as a user needs to makea selection and (3) the use of several GUI techniques which combine togive the user the sense that the entire interface resides on a singleplane, such that navigation of the GUI can be accomplished, andremembered, by way of the user's sense of direction. This latter aspectof GUIs according to the present invention can be accomplished by, amongother things, linking the various GUI screens together “geographically”by maintaining as much GUI object continuity from one GUI screen to thenext, e.g., by displaying edges of neighboring, unselected objectsaround the border of the current GUI screen. Alternatively, if a cleanerview is desired, and other GUI techniques provide sufficient geographicfeedback, then the clipped objects can be omitted. As used in this text,the phrase “GUI screen” refers to a set of GUI objects rendered on oneor more display units at the same time. A GUI screen may be rendered onthe same display which outputs media items, or it may be rendered on adifferent display. The display can be a TV display, computer monitor orany other suitable GUI output device.

Another GUI effect which enhances the user's sense of GUI screenconnectivity is the panning animation effect which is invoked when azoom is performed or when the user selects an adjacent object at thesame zoom level as the currently selected object. Returning to theexample of FIG. 5, as the user is initially viewing this GUI screen, hisor her point-of-view is centered about point 550. However, when he orshe selects Genre 3 for zooming in, his or her point-of-view will shiftto point 552. According to exemplary embodiments of the presentinvention, the zoom in process is animated to convey the shifting thePOV center from point 550 to 552. This panning animation can be providedfor every GUI change, e.g., from a change in zoom level or a change fromone object to another object on the same GUI zoom level. Thus if, forexample, a user situated in the GUI screen of FIG. 6 selected theleftmost unselected genre 515 (Genre 2), a panning animation would occurwhich would give the user the visual impression of “moving” left orwest. Exemplary embodiments of the present invention employ suchtechniques to provide a consistent sense of directional movement betweenGUI screens enables users to more rapidly navigate the GUI, both betweenzoom levels and between media items at the same zoom level.

Various data structures and algorithms can be used to implement zoomableGUIs according to the present invention. For example, data structuresand algorithms for panning and zooming in an image browser whichdisplays photographs have been described, for example, in the articleentitled “Quantum Treemaps and Bubblemaps for a Zoomable Image Browser”by Benjamin B. Bederson, UIST 2001, ACM Symposium on User InterfaceSoftware and Technology, CHI Letters, 3(2), pp. 71-80, the disclosure ofwhich is incorporated here by reference. However, in order to provide aGUI for media selection which can, at a high level, switch betweennumerous applications and, at a lower level, provide user controlsassociated with selected images to perform various media selectionfunctions, additional data structures and algorithms are needed.

Zoomable GUIs can be conceptualized as supporting panning and zoomingaround a scene of user interface components in the view port of adisplay device. To accomplish this effect, zoomable GUIs according toexemplary embodiments of the present invention can be implemented usingscene graph data structures. Each node in the scene graph representssome part of a user interface component, such as a button or a textlabel or a group of interface components. Children of a node representgraphical elements (lines, text, images, etc.) internal to that node.For example, an application can be represented in a scene graph as anode with children for the various graphical elements in its interface.Two special types of nodes are referred to herein as cameras and layers.Cameras are nodes that provide a view port into another part of thescene graph by looking at layer nodes. Under these layer nodes userinterface elements can be found. Control logic for a zoomable interfaceprogrammatically adjusts a cameras view transform to provide the effectof panning and zooming.

FIG. 9 shows a scene graph that contains basic zoomable interfaceelements which can be used to implement exemplary embodiments of thepresent invention, specifically it contains one camera node 900 and onelayer node 902. The dotted line between the camera node 900 and layernode 902 indicates that the camera node 900 has been configured torender the children of the layer node 902 in the camera's view port. Theattached display device 904 lets the user see the camera's view port.The layer node 902 has three children nodes 904 that draw a circle and apair of ovals. The scene graph further specifies that a rectangle isdrawn within the circle and three triangles within the rectangle by wayof nodes 912-918. The scene graph is tied into other scene graphs in thedata structure by root node 920. Each node 906-918 has the capability ofscaling and positioning itself relative to its parent by using a localcoordinate transformation matrix. FIGS. 10( a) and 10(b) illustrate whatthe scene graph appears like when rendered through the camera at afirst, zoomed out level of magnification and a second, zoomed in levelof magnification, respectively.

Rendering the scene graph can be accomplished as follows. Whenever thedisplay 904 needs to be updated, e.g., when the user triggers a zoom-infrom the view of FIG. 10( a) to the view of FIG. 10( b), a repaint eventcalls the camera node 900 attached to the display 904 to render itself.This, in turn, causes the camera node 900 to notify the layer node 902to render the area within the camera's view port. The layer node 902renders itself by notifying its children to render themselves, and soon. The current transformation matrix and a bounding rectangle for theregion to update is passed at each step and optionally modified toinform each node of the proper scale and offset that they should use forrendering. Since the scene graphs of applications operating withinzoomable GUIs according to the present invention may contain thousandsof nodes, each node can check the transformation matrix and the area tobe updated to ensure that their drawing operations will indeed be seenby the user. Although the foregoing example, describes a scene graphincluding one camera node and one layer node, it will be appreciatedthat exemplary embodiments of the present invention can embed multiplecameras and layers. These embedded cameras can provide user interfaceelements such as small zoomed out maps that indicate the user's currentview location in the whole zoomable interface, and also allow userinterface components to be independently zoomable and pannable.

When using a zoomable interface to coordinate the operation of multipleapplications, e.g., like the exemplary movie browser described belowwith respect to FIGS. 14-18, the memory and resource requirements foreach application may exceed the total memory available in the mediasystem. This suggests that applications unload some or all of their codeand data when the user is no longer viewing them. However, in zoomableGUIs according to the present invention it can be desirable to providethe appearance that some or all of the applications appear active to theuser at all times. To satisfy these two competing objectives, theapplications which are “off-screen” from the user's point of view can beput into a temporarily suspended state. To achieve this behavior inzoomable GUIs according to exemplary embodiments of the presentinvention, events are sent to applications to indicate when they enterand exit a view port. One way to implement such events is to add logicto the code that renders a component so that it detects when the userenters a view port. However, this implies that the notification logicgets invoked at every rendering event and, more importantly, that itcannot easily detect when the user has navigated the view port away fromthe component. Another method for sending events to applications is toincorporate the notification logic into the GUI navigation elements(such as hyperlinks and buttons), so that they send notifications to thecomponent when they change the view port of a camera to include thecomponent of interest. However, this requires the programmer tovigilantly add notification code to all possible navigation UI elements.

According to one exemplary embodiment, a computationally efficient nodewatcher algorithm can be used to notify applications regarding when GUIcomponents and/or applications enter and exit the view of a camera. At ahigh level, the node watcher algorithm has three main processing stages:(1) initialization, (2) view port change assessment and (3) scene graphchange assessment. The initialization stage computes node quantitiesused by the view port change assessment stage and initializesappropriate data structures. The view port change assessment stage getsinvoked when the view port changes and notifies all watched nodes thatentered or exited the view port. Finally, the scene graph changeassessment stage updates computations made at the initialization stagethat have become invalid due to changes in the scene graph. For example,if an ancestor node of the watched node changes location in the scenegraph, computations made at initialization may need to be recomputed.

Of these stages, view port change assessment drives the rest of the nodewatcher algorithm. To delineate when a node enters and exits a viewport, the initialization step determines the bounding rectangle of thedesired node and transforms it from its local coordinate system to thelocal coordinate system of the view port. In this way, checking nodeentrance does not require a sequence of coordinate transformations ateach view port change. Since the parents of the node may have transformmatrices, this initialization step requires traversing the scene graphfrom the node up to the camera. As described below, if embedded camerasare used in the scene graph data structure, then multiple boundingrectangles may be needed to accommodate the node appearing in multipleplaces.

Once the bounding rectangle for each watched node has been computed inthe view port coordinate system, the initialization stage adds thebounding rectangle to the view port change assessment data structures.The node watcher algorithm uses a basic building block for eachdimension in the scene. In zoomable interfaces according to someexemplary embodiments, this includes an x dimension, a y dimension, anda scale dimension. As described below, however, other exemplaryimplementations may have additional or different dimensions. The scaledimension describes the magnification level of the node in the view portand is described by the following equation:

$s = \frac{d^{\prime}}{d}$Where s is the scale, d is the distance from one point of the node toanother in the node's local coordinates and d′ is the distance from thatpoint to the other in the view port.

FIG. 11 shows an exemplary building block for detecting scene entranceand exit in one dimension. The following describes handling in the xdimension, but those skilled in the art will appreciate that the otherdimensions can be handled in a similar manner. The Region Block 1100contains references to the transformed bounding rectangle coordinates.This includes the left and right (top and bottom or minimum and maximumscale) offsets of the rectangle. The left and right offsets are storedin Transition Blocks 1102 and 1104, respectively, that are themselvesplaced in an ordered doubly linked list, such that lower numberedoffsets are towards the beginning. The current view port bounds arestored in the View Bounds block 1106. Block 1106 has pointers to theTransition Blocks just beyond the left and right side of the view, e.g.,the Transition Block immediately to the right of the one pointed to byView Left Side is in the view unless that latter block is pointed to byView Right Side.

When the view port changes, the following processing occurs for eachdimension. First, the View Left Side and View Right Side pointers arechecked to see if they need to be moved to include or exclude aTransition Block. Next, if one or both of the pointers need to be moved,they are slid over the Transition Block list to their new locations.Then, for each Transition Block passed by the View Left Side and ViewRight Side pointers, the node watcher algorithm executes the TransitionBlock notification code described below. This notification codedetermines if it is possible that its respective node may have enteredor exited the view port. If so, that node is added to a post processinglist. Finally, at the end of this processing for each dimension, eachnode on the post processing list is checked that its view port statusactually did change (as opposed to changing and then changing back). Ifa change did occur, then the algorithm sends an event to the component.Note that if the view port jumps quickly to a new area of the zoomableinterface that the algorithm may detect more spurious entrance and exitevents.

The Transition Block notification code can be implemented as a tablelookup that determines whether the node moved into or out of the viewport for the dimension being checked. An exemplary table is shown below.

TABLE 1 Transition Notification Table Node View View Move PartialIntersection Full intersection side side Direction NotificationNotification Left Left Left None Enter Left Left Right None Exit RightLeft Left Enter None Right Left Right Exit None Left Right Left ExitNone Left Right Right Enter None Right Right Left None Exit Right RightRight None EnterColumns 1, 2 and 3 are the inputs to the Transition Notification Table.Specifically, the node watcher algorithm addresses the table using acombination of the node side, view side and view move direction todetermine whether the node being evaluated was entered, exited or notimpacted. Column 1 refers to the side of the node represented by theTransition Block that was passed by the view port pointers. Column 2refers to the side of the view port and column 3 refers to the directionthat that side of the view port was moving when it passed the node'sTransition Block. Either output column 4 or 5 is selected depending uponwhether the node should be notified when it is partially or fully inview. For example, in some implementations it may be desirable to notifyan application such as a streaming video window only after it is fullyin view since loading a partially-in-view video window into the zoomableGUI may be visually disruptive.

When the output of the table indicates enter or exit, the node watcheralgorithm adds the node to the post processing list. The output columnsof Table 1 are populated based on the following rules. If the nodeintersects in all dimensions then an enter notification will be sent inthe post processing step. If the node was in the view and now one ormore dimensions have stopped intersecting, then an exit notificationwill be sent. To reduce the number of nodes in the post processing list,the Transition Block notification code checks for intersection withother dimensions before adding the node to the list. This eliminates thepost processing step when only one or two dimensions out of the totalnumber of dimensions, e.g., three or more, intersect. When a userinterface object (e.g., an application) wants to be notified of its viewport status in the GUI, it registers a function with the node watcheralgorithm. When the application goes into or out of the view, the nodewatcher algorithm calls that application's registered function with aparameter that indicates what happened. Alternatively, notification canbe performed using message passing. In this case, each application hasan event queue. The application tells the node watcher algorithm how tocommunicate with its event queue. For example, it could specify thequeue's address. Then, when the node watcher detects a transition, itcreates a data structure that contains the cause of the notification andplaces it in the application's queue.

In addition to using node watcher notifications for application memorymanagement, this algorithm can also be used for other functions inzoomable GUIs according to the present invention. For example, the nodewatcher algorithm can be used to change application behavior based onthe user's view focus, e.g., by switching the audio output focus to thecurrently viewed application. Another application for the node watcheralgorithm is to load and unload higher resolution and composite imageswhen the magnification level changes. This reduces the computationalload on the graphics renderer by having it render fewer objects whoseresolution more closely matches the display. In addition to having thenode watcher algorithm watch a camera's view port, it is also useful tohave it watch the navigation code that tells the view port where it willend up after an animation. This provides earlier notification ofcomponents that are going to come into view and also enables zoomableGUIS according to exemplary embodiments of the present invention toavoid sending notifications to nodes that are flown over due to panninganimations.

To better understand operation of the node watcher algorithm, an examplewill now be described with reference to FIGS. 12( a), 12(b), 13(a) and13(b). FIGS. 12( a) and 12(b) depict a portion of a zoomable GUI at twodifferent magnification levels. At the lower magnification level of FIG.12( a), three nodes are visible: a circle, a triangle and an ellipse. InFIG. 12( b), the view has been zoomed in so much that the ellipse andcircle are only partially visible, and the triangle is entirely outsideof the view. These nodes may, for example, represent applications oruser interface components that depend on efficient event notificationand, therefore, are tracked by the node watcher algorithm according toexemplary embodiments of the present invention. In this example, thebounding rectangles for each node are explicitly illustrated in FIGS.12( a) and 12(b) although those skilled in the art will appreciate thatthe bounding rectangles would not typically be displayed on the GUI.Each side of each of the bounding rectangles has been labeled in FIGS.12( a) and 12(b), and these labels will be used to show thecorrespondence between the bounding rectangle sides and the transitionblock data structure which were described above.

FIG. 13( a) shows exemplary node watcher data structures for thehorizontal dimension for the zoomed out view of FIG. 12( a). Therein,each side of a node's bounding rectangle is represented using atransition block. The horizontal transition blocks are shown in FIG. 13(a) in the order that they appear on the GUI screen from left to right.For example, the left side of the circle, C_(Left), comes first and thenthe left side of the triangle, T_(Left), and so on until the right sideof the ellipse, E_(Right). Both ends of the list are marked with emptysentinel transition blocks. Also shown in FIG. 13( a) are the regionblocks for each node and their corresponding pointers to their boundingrectangle's horizontal transition blocks. At the bottom of FIG. 13( a)is the view bounds data structure that contains pointers to thetransition blocks that are just outside of the current view. For thezoomed out view, all nodes are completely visible, and therefore all oftheir transition blocks are between the transition blocks pointed to bythe view bounds data structure.

FIG. 13( b) shows the node watcher data structures for the zoomed inview of FIG. 12( b). Therein, it can be seen that the view bounds partof the data structure has changed so that it now points to thetransition blocks for the right side of the triangle, T_(Right), and theright side of the ellipse, E_(Right), since these two bounding rectanglesides are just outside of the current (zoomed in) view.

Given these exemplary data structures and GUI scenes, the associatedprocessing within the node watcher algorithm while the zoom transitionoccurs can be described as follows. Starting with the left side of theview, the node watcher algorithm moves the view left side pointer to theright until the transition block that is just outside of the view on theleft side is reached. As shown in FIG. 13( b), the view left sidepointer first passes the C_(Left) transition block. For this example,assume that the circle node represents an application or other userinterface object associated with the zoomable GUI that requires anotification when it is not fully visible in the view. Given theseinputs to the node watcher algorithm, Table 1 indicates that the circlenode should receive an exit notification for the horizontal dimension.Of course, the node watcher algorithm will typically aggregatenotifications from all dimensions before notifying the node to avoidsending redundant exit notifications. Next, the view left side pointerpasses the left side of the triangle, T_(Left). If the triangle node hasrequested notifications for when it completely leaves the view, then thenode watcher algorithm indicates per Table 1 that no notification isnecessary. However, when the view pointer passes T_(Right), Table 1indicates that the triangle has exited the view entirely and should benotified. The view pointer stops here since the right side of thecircle's bounding rectangle, C_(Right), is still visible in the view.

From the right side, the node watcher algorithm's processing is similar.The view right side pointer moves left to the ellipse's right sideE_(Right). Depending on whether the ellipse has requested full orpartial notifications, the node watcher algorithm will or will not senda notification to the ellipse pursuant to Table 1. The verticaldimension can be processed in a similar manner using similar datastructures and the top and bottom boundary rectangle values. Thoseskilled in the arts will also appreciate that a plurality of boundaryrectangles can be used to approximate non-rectangular nodes when moreprecise notification is required. Additionally, the present inventioncontemplates that movement through other dimensions can be tracked andprocessed by the node watcher algorithm, e.g., a third geometrical(depth or scale) dimension, as well as non-geometrical dimensions suchas time, content rating (adult, PG-13, etc.) and content type (drama,comedy, etc). Depending on the number of dimensions in use, thealgorithm, more accurately, detects intersections of boundary segments,rectangles, and n-dimensional hypercubes.

In addition to the node watcher algorithm described above, exemplaryembodiments of the present invention provide resolution consistentsemantic zooming algorithms which can be used in zoomable GUIs accordingto exemplary embodiments of the present invention. Semantic zoomingrefers to adding, removing or changing details of a component in azoomable GUI depending on the magnification level of that component. Forexample, in the movie browser interface described below, when the userzooms close enough to the image of the movie, it changes to show moviemetadata and playback controls. The calculation of the magnificationlevel is based on the number of pixels' that the component uses on thedisplay device. The zoomable GUI can store a threshold magnificationlevel which indicates when the switch should occur, e.g., from a viewwithout the movie metadata and playback controls to a view with themovie metadata and playback controls.

Television and computer displays have widely varying displayresolutions. Some monitors have such a high resolution that graphics andtext that is readable on a low resolution display is so small to becomecompletely unreadable. This also creates a problem for applications thatuse semantic zooming, especially on high resolution displays such asHDTVs. In this environment, semantic zooming code that renders based onthe number of pixels displayed will change the image before the moredetailed view is readable. Programmatically modifying the threshold atwhich semantic zooming changes component views can only work for oneresolution.

The desirable result is that semantic zooming occurs consistently acrossall monitor resolutions. One solution is to use lower resolution displaymodes on high resolution monitors, so that the resolution is identicalon all displays. However, the user of a high resolution monitor wouldprefer that graphics would be rendered at their best resolution ifsemantic zooming would still work as expected. Accordingly, exemplaryembodiments of the present invention provide a semantic zoomingtechnique which supports displays of all different resolutions withoutthe previously stated semantic viewing issues. This can be accomplishedby, for example, creating a virtual display inside of the scene graph.This is shown in FIG. 14 by using an embedded virtual camera node 1200and adding logic to compensate for the display resolution. The virtualcamera node 1200 defines a view port whose size maps to the user's viewdistance and monitor size. For example, a large virtual camera view portindicates that a user is either sitting close enough to the monitor orhas a large enough monitor to resolve many details. Alternately, a smallview port indicates that the user is farther away from the monitor andrequires larger fonts and image. The zoomable GUI code can base thesemantic zooming transitions on the magnification level of componentsseen on this virtual camera and using the user's preferred viewingconditions.

The main camera node 1202 that is attached to the display device 1204has its view port configured so that it displays everything that thevirtual camera 1200 is showing. Since graphics images and text are notmapped to pixels until this main camera 1202, no loss of quality occursfrom the virtual camera. The result of this is that high definitionmonitors display higher quality images and do not trigger semanticzooming changes that would make the display harder to read.

According to one exemplary embodiment of the present invention, theprocess works as follows. Each camera and node in the scene graph has anassociated transform matrix (T₁ to T_(n)). These matrices transform thatnode's local coordinate system to that of the next node towards thedisplay. In the figure, T₁ transforms coordinates from its view port todisplay coordinates. Likewise, T₂ transforms its local coordinate systemto the camera's view port. If the leaf node 1206 needs to rendersomething on the display, it computes the following transform matrix:A=T₁T₂ . . . T_(n)This calculation can be performed while traversing the scene graph.Since the component changes to support semantic zooming are based on thevirtual camera 1200, the following calculation is performed:B=T₄T₅ . . . T_(n)Typically, T₁ to T₃ can be determined ahead of time by querying theresolution of the monitor and inspecting the scene graph. Determining Bfrom A is, therefore, accomplished by inverting these matrices andmultiplying as follows:B=(T ₁ T ₂ T ₃)⁻¹ AFor the case when calculating T₁ to T₃ ahead of time is problematic,e.g., if a graphics API hides additional transformations, logic can beadded to the virtual camera to intercept the transformation matrix thatit would have used to render to the display. This interceptedtransformation is then inverted and multiplied as above to compute thesemantic zooming threshold.

One strength of zoomable interfaces according to exemplary embodimentsof the present invention is the ability to maintain context whilenavigating the interface. All of the interface components appear toexist in the zoomable world, and the user just needs to pan and zoom toreach any of them. The semantic zooming technique described abovechanges the appearance of a component depending on the zoom ormagnification level. FIGS. 15( a) and 15(b) provide an example ofsemantic zooming for a component where the zoomed out version of thecomponent (FIG. 15( a)) is a picture and the zoomed in version (FIG. 15(b)) includes the same picture as well as some controls and details. Somemore detailed examples of this are provided below. One challengeassociated with semantic zooming is that changes between views can occurabruptly, and transition techniques such as alpha blending do notprovide visually pleasing results when transitioning between two suchviews.

Accordingly, exemplary embodiments of the present invention provide forsome common image or text in all views of a component to provide a focalpoint for a transition effect when a semantic zoom is performed. Forexample, in FIGS. 15( a) and 15(b), the common element is the picture.The transition effect between the zoomed out version and the zoomed inversion can be triggered using, for example, the above-described nodewatcher algorithm as follows. First, a registration with the nodewatcher can be performed to receive an event when the main camera's viewport transitions from the magnification level of the zoomed out versionof the component to the zoomed in version. Then, when the event occurs,an animation can be displayed which shows the common element(s)shrinking and translating from their location in the zoomed out versionto their location in the zoomed in version. Meanwhile, the camera's viewport continues to zoom into the component.

These capabilities of graphical user interfaces according to the presentinvention will become even more apparent upon review of anotherexemplary embodiment described below with respect to FIGS. 16-20.Therein, a startup GUI screen 1400 displays a plurality of organizingobjects which operate as media group representations. The purelyexemplary media group representations of home video, movies, TV, sports,radio, music and news could, of course include different, more or fewermedia group representations. Upon actuation of one of these icons by auser, the GUI according to this exemplary embodiment will then display aplurality of images each grouped into a particular category or genre.For example, if the “movie” icon in FIG. 16 was actuated by a user, theGUI screen of FIG. 17 can then be displayed. Therein, a large number,e.g., 120 or more, selection objects are displayed. These selectionobjects can be categorized into particular group(s), e.g., action,classics, comedy, drama, family and new releases. Those skilled in theart will appreciate that more or fewer categories could be provided. Inthis exemplary embodiment, the media item images can be cover artassociated with each movie selection. Although the size of the blocks inFIG. 17 is too small to permit detailed illustration of this relativelylarge group of selection item images, in implementation, the level ofmagnification of the images is such that the identity of the movie canbe discerned by its associated image, even if some or all of the textmay be too small to be easily read.

The cursor (not shown in FIG. 17) can then be disposed over a group ofthe movie images and the input device actuated to provide a selectionindication for one of the groups. In this example the user selects thedrama group and the graphical user interface then displays a zoomedversion of the drama group of images as seen in FIG. 18. As with theprevious embodiment, a transition effect can also be displayed as theGUI shifts from the GUI screen of FIG. 17 to the GUI screen of FIG. 18,e.g., the GUI may pan the view from the center of the GUI screen of FIG.17 to the center of the drama group of images during or prior to thezoom. Note that although the zoomed version of the drama group of FIG.18 only displays a subset of the total number of images in the dramagroup, that this zoomed version can alternatively contain all of theimages in the selected group. The choice of whether or not to displayall of the images in a selected group in any given zoomed in version ofa GUI screen can be made based upon, for example, the number of mediaitems in a group and a minimum desirable magnification level for a mediaitem for a particular zoom level. This latter characteristic of GUIsaccording to the present invention can be predetermined by the systemdesigner/service provider or can be user customizable via softwaresettings in the GUI. For example, the number of media items in a groupand the minimum and/or maximum magnification levels can be configurableby either or both of the service provider or the end user. Such featuresenable those users with, for example, poor eyesight, to increase themagnification level of media items being displayed. Conversely, userswith especially keen eyesight may decrease the level of magnification,thereby increasing the number of media items displayed on a GUI screenat any one time and decrease browsing time.

One exemplary transition effect which can be employed in graphical userinterfaces according to the present invention is referred to herein asthe “shoe-to-detail” view effect. When actuated, this transition effecttakes a zoomed out image and simultaneously shrinks and translates thezoomed out image into a smaller view, i.e., the next higher level ofmagnification. The transition from the magnification level used in theGUI screen of FIG. 17 to the greater magnification level used in the GUIscreen of FIG. 18 results in additional details being revealed by theGUI for the images which are displayed in the zoomed in version of FIG.18. The GUI selectively reveals or hides details at each zoom levelbased upon whether or not those details would display well at thecurrently selected zoom level. Unlike a camera zoom, which attempts toresolve details regardless of their visibility to the unaided eye,exemplary embodiments of the present invention provide for aconfigurable zoom level parameter that specifies a transition pointbetween when to show the full image and when to show a version of theimage with details that are withheld. The transition point can be basedupon an internal resolution independent depiction of the image ratherthe resolution of TV/Monitor 212. In this way, GUIs according to thepresent invention are consistent regardless of the resolution of thedisplay device being used in the media system.

In this exemplary embodiment, an additional amount of magnification fora particular image can be provided by passing the cursor over aparticular image. This feature can be seen in FIG. 19, wherein thecursor has rolled over the image for the movie “Apollo 13”. Although notdepicted in FIG. 19, such additional magnification could, for example,make more legible the quote “Houston, we have a problem” which appearson the cover art of the associated media item as compared to thecorresponding image in the GUI screen of FIG. 18 which is at a lowerlevel of magnification. User selection of this image, e.g., bydepressing a button on the input device, can result in a further zoom todisplay the details shown in FIG. 20. This provides yet another exampleof semantic zooming as it was previously described since variousinformation and control elements are present in the GUI screen of FIG.20 that were not available in the GUI screen of FIG. 19. For example,information about the movie “Apollo 13” including, among other things,the movie's runtime, price and actor information is shown. Those skilledin the art will appreciate that other types of information could beprovided here. Additionally, this GUI screen includes GUI controlobjects including, for example, button control objects for buying themovie, watching a trailer or returning to the previous GUI screen (whichcould also be accomplished by depressing the ZOOM OUT button on theinput device). Hyperlinks can also be used to allow the user to jump to,for example, GUI screens associated with the related movies identifiedin the lower right hand corner of the GUI screen of FIG. 20 orinformation associated with the actors in this movie. In this example,some or all of the film titles under the heading “Filmography” can beimplemented as hyperlinks which, when actuated by the user via the inputdevice, will cause the GUI to display a GUI screen corresponding to thatof FIG. 20 for the indicated movie.

A transition effect can also be employed when a user actuates ahyperlink. Since the hyperlinks may be generated at very highmagnification levels, simply jumping to the linked media item may causethe user to lose track of where he or she is in the media item selection“map”. Accordingly, exemplary embodiments of the present inventionprovide a transition effect to aid in maintaining the user's sense ofgeographic position when a hyperlink is actuated. One exemplarytransition effect which can be employed for this purpose is a hoptransition. In an initial phase of the transition effect, the GUI zoomsout and pans in the direction of the item pointed to by the hyperlink.Zooming out and panning continues until both the destination image andthe origination image are viewable by the user. Using the example ofFIG. 20 once again, if the user selects the hyperlink for “SavingPrivate Ryan”, then the first phase of the hyperlink hop effect wouldinclude zooming out and panning toward the image of “Saving PrivateRyan” until both the image for “Saving Private Ryan” and “Apollo 13”were visible to the user. At this point, the transition effect hasprovided the user with the visual impression of being moved upwardly inan arc toward the destination image. Once the destination image is inview, the second phase of the transition effect gives the user thevisual impression of zooming in and panning to, e.g., on the other halfof the arc, the destination image. The hop time, i.e., the amount oftime both phases one and two of this transition effect are displayed,can be fixed as between any two hyperlinked image items. Alternatively,the hop time may vary, e.g., based on the distance traveled over theGUI. For example, the hop time can be parameterized as HopTime=Alog(zoomed-in scale level/hop apex scale level)+B(distance betweenhyperlinked media items)+C, where A, B and C are suitably selectedconstant values.

The node watcher algorithm described above with respect to FIGS. 9-13(b) can also be used to aid in the transition between the zoom leveldepicted in the exemplary GUI screen of FIG. 19 and the exemplary GUIscreen of FIG. 20. The rendering of GUI screens containing text and/orcontrol elements which are not visible in other zoom level versions ofthe selected image may be more computationally and/or memory intensivethan the images at lower magnification levels. Accordingly, the nodewatcher algorithm can be used in exemplary embodiments of the presentinvention to aid in pre-loading of GUI screens such as that shown inFIG. 20 by watching the navigation code of the GUI to more rapidlyidentify the particular media item being zoomed in on.

Included in exemplary implementations of the present invention arescreen-location and semantically-based navigation controls. Thesecontrol regions appear when the user positions the cursor near or in aregion associated with those controls on a screen where those controlsare appropriate as shown in FIG. 21. For example, when playing a movie,the so-called trick functions of Fast Forward, Rewind, Pause, Stop andso on are semantically appropriate. In this exemplary embodiment, thescreen region assigned to those functions is the lower right corner andwhen the cursor is positioned near or in that region, the set of iconsfor those trick functions appear. These icons then disappear when thefunction engaged is clearly completed or when the cursor is repositionedelsewhere on the screen. The same techniques can also be used to coverother navigational features like text search and home screen selection.In this exemplary implementation, these controls are semanticallyrelevant on all screens and the region assigned to them is the upperright corner. When the cursor is positioned near or in that region, theset of icons for those navigational controls appear. These icons thendisappear when the function is activated or the cursor is repositionedelsewhere on the screen. Note that for user training purposes, therelevant control icons may initially optionally appear briefly (e.g., 5seconds) on some or all of the relevant screens in order to alert theinexperienced user to their presence.

Having provided some examples of zoomable graphical user interfacesaccording to the present invention, exemplary frameworks andinfrastructures for using such interfaces will now be described. FIG. 22provides a framework diagram wherein zoomable interfaces associated withvarious high level applications 1900, e.g., movies, television, music,radio and sports, are supported by primitives 1902 (referred to in theFigure as “atoms”). In this exemplary embodiment, primitives 1902include POINT, CLICK, ZOOM, HOVER and SCROLL, although those skilled inthe art will appreciate that other primitives may be included in thisgroup as well, e.g., PAN and DRAG. As described above the POINT andCLICK primitives operate to determine cursor location and trigger anevent when, for example, a user actuates the ZOOM IN or ZOOM OUT buttonon the handheld input device. These primitives simplify navigation andremove the need for repeated up-down-right-left button actions. Asillustrated above, the ZOOM primitive provides an overview of possibleselections and gives the user context when narrowing his or her choices.This concept enables the interface to scale to large numbers of mediaselections and arbitrary display sizes. The SCROLL primitive handlesinput from the scroll wheel input device on the exemplary handheld inputdevice and can be used to, for example, accelerates linear menunavigation. The HOVER primitive dynamically enlarges the selectionsunderneath the pointer (and/or changes the content of the selection) toenable the user to browse potential choices without committing. Each ofthe aforedescribed primitive operations can be actuated in GUlsaccording to the present invention in a number of different ways. Forexample, each of POINT, CLICK, HOVER, SCROLL and ZOOM can be associatedwith a different gesture which can be performed by a user. This gesturecan be communicated to the system via the input device, whether it be afree space pointer, trackball, touchpad, etc. and translated into anactuation of the appropriate primitive. Likewise, each of the primitivescan be associated with a respective voice command.

Between the lower level primitives 1902 and the upper level applications1900 reside various software and hardware infrastructures 1904 which areinvolved in generating the images associated with zoomable GUIsaccording to the present invention. As seen in FIG. 22, suchinfrastructures 1904 can include a handheld input device/pointer,application program interfaces (APIs), zoomable GUI screens, developers'tools, etc.

The foregoing exemplary embodiments are purely illustrative in nature.The number of zoom levels, as well as the particular information andcontrols provided to the user at each level may be varied. Those skilledin the art will appreciate that the present invention providesrevolutionary techniques for presenting large and small sets of mediaitems using a zoomable interface such that a user can easily searchthrough, browse, organize and play back media items such as movies andmusic. Graphical user interfaces according to the present inventionorganize media item selections on a virtual surface such that similarselections are grouped together. Initially, the interface presents azoomed out view of the surface, and in most cases, the actual selectionswill not be visible at this level, but rather only their group names. Asthe user zooms progressively inward, more details are revealedconcerning the media item groups or selections. At each zoom level,different controls are available so that the user can play groups ofselections, individual selections, or go to another part of the virtualsurface to browse other related media items. Zooming graphical userinterfaces according to exemplary embodiments of the present inventioncan contain categories of images nested to an arbitrary depth as well ascategories of categories. The media items can include content which isstored locally, broadcast by a broadcast provider, received via a directconnection from a content provider or on a peering basis. The mediaitems can be provided in a scheduling format wherein date/timeinformation is provided at some level of the GUI. Additionally,frameworks and GUIs according to exemplary embodiments of the presentinvention can also be applied to television commerce wherein the itemsfor selection are being sold to the user.

The above-described exemplary embodiments are intended to beillustrative in all respects, rather than restrictive, of the presentinvention. Thus the present invention is capable of many variations indetailed implementation that can be derived from the descriptioncontained herein by a person skilled in the art. All such variations andmodifications are considered to be within the scope and spirit of thepresent invention as defined by the following claims. No element, act,or instruction used in the description of the present application shouldbe construed as critical or essential to the invention unless explicitlydescribed as such. Also, as used herein, the article “a” is intended toinclude one or more items.

1. A system having a graphical user interface (GUI) comprising: a firstplurality of graphical user interface objects, each representing a mediaitem, displayed at a first zoom level; means for receiving a selectionindication associated with one of said first plurality of graphical userinterface objects; and means for zooming in on, and panning toward, saidone of said first plurality of graphical user interface objects todisplay at least said one of said first plurality of graphical userinterface objects at a second zoom level, means for maintaining a datastructure which contains information associated with a local coordinatesystem for said interface object; means for transforming said localcoordinate system using a transform matrix to generate a resolutionindependent data set for said interface object; and means for mappingsaid resolution independent data set to pixels associated with acurrently displayed portion of said GUI, wherein, if said second zoomlevel exceeds a semantic zoom threshold, said semantic zoom threshold isbased, at least in part on a display resolution, said one of said firstplurality of graphical user interface objects includes different contentthan said one of said first plurality of graphical user interfaceobjects at said first zoom level.
 2. The graphical user interface ofclaim 1, wherein said second zoom level exceeds a semantic zoomthreshold.
 3. The GUI of claim 1, wherein said different content isadditional text information which was not visible at said first zoomlevel.
 4. The GUI of claim 1, wherein said different content includes atleast one GUI control object which was not visible at said first zoomlevel.
 5. The GUI of claim 4, wherein said at least one GUI controlobject is a hyperlink which provides a link to a different media item.6. The GUI of claim 4, wherein said at least one GUI control object is acontrol object which, when actuated, causes said GUI to play said mediaitem.
 7. The GUI of claim 1, wherein said media item is one of a movie,a song and a television channel.
 8. A method for media item selection ina media system comprising the steps of: displaying a plurality of mediaitems as images on a display screen of said media system; maintaining adata structure which contains information associated with a localcoordinate system for said media items; transforming said localcoordinate system using a transform matrix to generate a resolutionindependent data set for said media items; mapping said resolutionindependent data set to pixels associated with a currently displayedportion of said GUI; receiving user input to said media system; zoomingin on said plurality of media items based on said user input until atleast one control object is visible on said display screen, whereinzooming further comprises the step of: zooming in steps betweenpredetermined magnification levels, wherein each step is associated witha corresponding user input, further wherein one of said predeterminedmagnification levels represents a semantic zooming threshold and whereinsaid at least one control object becomes visible on said display screenwhen said semantic zooming threshold is reached and wherein saidsemantic zooming threshold is determined based upon a resolution of saiddisplay screen; and operating, by said user, one of said control objectsto select a corresponding media item.
 9. The method of claim 8, whereinsaid plurality of media items represent at least one of movies, songsand television channels.
 10. A method for displaying an interface objecton a graphical user interface (GUI) comprising the steps of: displayingan interface object at a first zoom level, wherein said interface objectis displayed with at least one feature removed therefrom; receiving acommand to zoom in on said interface object; determining that a zoomthreshold has been reached with respect to said removal of said at leastone feature, wherein said zoom threshold is determined based, at leastin part, on a resolution of a display device; and maintaining a datastructure which contains information associated with a local coordinatesystem for said interface object; transforming said local coordinatesystem using a transform matrix to generate a resolution independentdata set for said interface object; mapping said resolution independentdata set to pixels associated with a currently displayed portion of saidGUI; displaying said interface object at a second zoom level, whereinsaid at least one feature is included.
 11. The method of claim 10,wherein said at least one feature is a segment of text which is clippedfrom said interface object when displayed at said one of said pluralityof magnification levels.
 12. The method of claim 10, wherein said atleast one feature is a hyperlink.
 13. The method of claim 10, whereinsaid at least one feature is another interface object.
 14. The method ofclaim 10, wherein said step of determining that a zoom threshold hasbeen reached further comprises the step of: determining that said zoomthreshold has been reached if a number of said pixels in a predetermineddimension exceeds a threshold number of pixels.